1. Field of Invention
The invention relates to a flat platen that is provided in an image forming apparatus. The invention also relates to an image forming apparatus that detects both side edges of a recording sheet being fed therein.
2. Description of Related Art
Japanese Laid-Open Patent Publication No.2000-109243 discloses a conventional inkjet recording apparatus such as a printer and a facsimile machine. (Refer to pp 4-6 and FIG. 3.) The inkjet recording apparatus has a flat platen that guides a recording sheet that is fed horizontally therein and a print head that is movable in a vertical direction relative to a sheet feed direction. In the inkjet recording apparatus, a recording sheet is fed on the flat platen and the print head, which is disposed facing the recording sheet, is moved to eject ink onto the recording sheet, thereby printing is made.
The print head is provided with a light emitting device (a light emitting diode, LED) and a light receiving device (a photo transistor) for detecting a width of a recording sheet. When light emitted from the light emitting device reflects on a recording sheet and is received at the light receiving device, a side edge of the sheet being fed parallel to the sheet feed direction is detected. With the detection of the side edge, a print start position and a print end position with respect to a scanning direction of the print head are determined.